Waveguide switch



June 25, 1968 J. VLIETSTRA 3,390,355

WAVEGUIDE SWITCH Filed Sept. 29, 1965 3 Sheets-Sheet 1 INVENTOR. JAN VLIETSTRA AGEN June 25,1968 7 VLIETSTRA 3,390,355

WAVEGUIDE SWITCH Filed Sept. 29, 1965 5 Sheets-Sheet t1 INVENTOR.

JAN VLIETS TRA AGENT June 25, 1968 J. VLIEITSTRA 3,390,355

WAVEGUIDE SWITCH Filed Sept. 29, 1965 5 Sheets-Sheet 5 Fig.3

INVENTOR.

JAN VLIETSTRA AGENT United States Patent 3,390,355 WAVEGUIDE SWITCH Jan Vlietstra, Hengelo, Overijsel, Netherlands, assignor to N. V. Hollandse Signaalapparaten, Hengelo, Overijsel, Netherlands, a firm of The Netherlands Filed Sept. 29, 1965, Ser. No. 491,158 Claims priority, application Netherlands, Oct. 2, 1964, 6411466 6 Claims. (Cl. 333-7) ABSTRACT OF THE DISCLOSURE A waveguide switch has three ports, and a pivoted vane mounted to permit selective interconnection of one of the ports to either of the other ports. The vane is provided with plates at its ends that provide capacitive coupling with the adjacent switch walls, in order to permit switching of the device while high frequency power is applied to it.

T he invention relates to a waveguide switch of the type comprising in combination: a delta-shaped body having first, second, and third waveguide passages passing normally inwardly from the fiat faces of said body respectively to intersect in the central portion of said body at angles of 120 with respect to each other; a vane of rectangular dimensions; a shaft secured to one longitudinal edge of said vane, and means in said body rotatably mounting said shaft in alignment with the line of intersection of the two adjacent walls of said second and third passages.

Switching devices of this type find wide application in radar systems. They permit two waveguides respectively fitted to the second and third waveguide passages to be alternately connected to a third waveguide fitted to the said first passage, simply by swinging the vane between a first and a second position. The physical construction of these known switching devices makes them suitable for a wide frequency band, while at the same time minimum power loss between connected waveguide passages and maximum isolation between disconnected passages may be realised. In practice, however, it is felt to be a serious drawback that this known construction does not permit the switching operation to take place under full power, owing to the arcing and sparking which thereby occurs at the short edges of the vane, eventually resulting in a baking together of vane and switch body.

It is the object of this invention to provide a waveguide switch, which, while retaining the aforementioned advantages, permits the switching operation to take place under full power. By the term full power is meant the maximum power the said waveguides can transfer without the occurrence of an electrical disruptive discharge within the said waveguides.

According to the invention in a waveguide switch of the type described, the rotatable vane at its short edges is provided with means fixedly connected to said vane and forming a capacitive coupling with the adjacent narrow internal wall of the said switch body parallel thereto which for the high frequency energy supplied functions as a short-circuit.

In order that the invention may readily be carried into effect, it will now be described in greater detail with reference to the accompanying drawings in which:

FIG. 1 shows in perspective the waveguide switch according to the invention as well as the rectangular waveguides to be connected thereto;

FIG. 2 shows a cross section through the centre of the said waveguide switch;

FIG. 3 shows a longitudinal cross section through the centre of the waveguide switch and in the direction of the arrows perpendicular to the line IIIIII in FIG. 2;

3,390,355 Patented June 25, 1968 FIG. 4 and FIG. 5 show in perspective two possible embodiments of the vane as used in the waveguide switch according to the invention.

Referring to FIG. 1, there is shown a waveguide switch 10 having fiat faces arranged to receive the rectangular wave guides 11, 12 and 13. The waveguide switch is provided with a switching member (not visible) which in accordance with its two operating positions can alternately connect the wave guides 12 and 13 to the waveguide 11.

As shown in FIG. 2 the waveguide switch comprises a delta-shaped switch body 14 having three waveguide passages 15, 16 and 17 passing normally inwardly from the flat faces of said body respectively to intersect in the central portion of said body at angles of with respect to each other. The said switching member consists of a vane 18 of rectangular dimensions. To one longitudinal edge of said vane a shaft 19 is secured which is rotatably mounted in alignment with the line of intersection of the two adjacent walls 20 and 21 of said second and third passages. Dependent on its switching position the vane closes either the one or the other of the last mentioned passages for the high frequency electro-rnagnetic energy that is supplied to the first waveguide passage 15.

In accordance with the invention a particularly favourable and in every respect advantageous embodiment of such a waveguide switch is obtained if the rotatable vane as shown in FIG. 4, at its short edges is provided with means 22, 23 fixedly connected to said vane and each forming a capacitive coupling with the adjacent narrow internal wall of the said switch body parallel thereto. The capacitive coupling functions as a short circuit for the high frequency energy supplied.

The vane as used in the waveguide switch of FIGS. 2 and 3 may be shaped as shown in FIG. 4. In this embodiment of the vane the said fixedly connected means consists of rectangular traverse plates 22 and 23 which are each divided into two equal parts by the plane of the vane. The vane including the traverse plates 22 and 23 is made of electrically conductive material.

The rectangular dimensions of the vane are chosen to be such that the short edges of said vane are somewhat longer than the width (see FIG. 3, dimension a) of the rectangular waveguide passages. As a result the longitudinal edge that is not connected to the shaft 19 rests in each one of the two switching positions of the vane against one of the internal walls 24 or 25 of the waveguide passage 15, making a direct electrical and mechanical contact with the walls of said passage. The longitudinal edge of the vane, on the other hand, is chosen to be so much smaller than the height (dimension [2) of the waveguide passages, that narrow gaps 26 and 27 are present between said traverse plates 22 and 23 respectively and the top and bottom respectively of the waveguide passages. Provided the height of the narrow gaps 26 and 27 and the traverse plates 22 and 23 respectively are properly dimensioned they appear to provide an apparent current path between the vane 18 and the top and bottom respectively of the wavguide passages. This ensures a maximum isolation between the not-connected waveguides, and the traverse plates 22 and 23 moreover completely suppress the tendency to are and spark. It is a further advantage of the waveguide switch that the vane 18 (including the traverse plates 22 and 23), may be made of thin material as illustrated by FIG. 4. Accordingly the vane will be of small weight thus permitting a short switching time, while, as only small power is needed for the rotation of the vane, the required driving means may be simple.

In the shown embodiment of the waveguide switch two electromagnetic driving arrangements are provided which, as illustrated in FIG. 3, are fitted into cylindrically shaped housings 28 and 28', respectively. The driving arrangement fitted in the house 28 consists of a coil 30 arranged on a coil holder 29 in which a plunger 31 can move up and down. One of the extremities of the plunger 31 is provided with a helical groove 32 which cooperates with a protruding part of the coil holder 29 which part extends radially into the said groove, thus causing the up and down movement of the plunger to be translated in a rotational movement, which by way of the gear transmission 34, 35 drives the shaft 19 of the vane 18.

The coil holder 29 is provided at one of its extremities with a cover plate 36 onto which a contact arm 37 is mounted. This contact arm cooperates with a fixed contact 38. Against the contact arm 37 rests a pin 39 of insulating material which extends through a hole in the cover plate and which is carried by the plunger 31. The housing 28 is provided with a cover 40 through which four contact pins 41, 42, 43 and 44 are fed. The contact pins 41 and 42 are connected to the coil 30, and the contact pins 43 and 44 are connected to the contact arm 37 and the fixed contact 38 respectively.

The driving arrangement mounted in the housing 28' is of the same construction. Corresponding parts are therefore provided with the same reference numerals, which, however, for the sake of clarity are provided with an accent. The waveguide switch described in the foregoing operates as follows:

In FIG. 3 the plungers 31 and 31' are shown in the position they are in when the coil 30' is excited by a source (not shown) feeding the coil by way of the contact pins 41' and 42. The vane 18 will then be in the position which in FIG. 2 is shown in full lines, whereby the waveguide passage 16 is closed so that the applied high frequency electro-magnetic energy can pass only via the waveguide passage 17.

This switching position is reported back via the contacts 47 and 48, which in this position of the switch rest against each other.

When now the coil 30 is excited instead of the coil 30', the plunger 31 moves upwards, while rotating in the anti-clockwise direction. By this rotation of the plunger 31 the shaft 19 is driven by way of the gear transmission 34, 35, with the result that the vane 18 is brought in the switching position which in FIG. 2 is indicated by dotted lines. In this switching positon the wave guide passage 17 is closed so that the high frequency electro-rnagnetic energy can pass only via the waveguide passage 16. The rotation of the shaft 19, which occurs in consequence of the upward movement of the plunger 31, is transferred by way of the gear transmission 34', 35', to the plunger 31, which accordingly moves along with the movement of the plunger 31 in the upward direction. This causes the switch formed by the contact arms 37' and the fixed contact 38' to be opened, so that the reporting back circuit, which is connected to the contact pins 43' and 44' is interrupted. The moment the vane 18 attains the switching position which in FIG. 2 is indicated by dotted lines, a reporting back circuit (not shown) connected to the contact pins 43 and 44 is closed by way of the contacts 37 and 38 being pressed together by the pin 39.

During this switching operation the vane swings in a very short time through an angle of from the one to the other switching position. The input impedance of the waveguide passage, closed at first, continuously decreases during this switching operation whereas the input impedance of the waveguide passage, open at first, increases. During this switching operation the vane divides the energy which is supplied by way of the waveguide passage 15 between the two waveguide passages 16 and 17 in proportion to the said input impedances.

This feature of the waveguide switch, in combination with the use of a vane which is provided with traverse plates as described, is very important, because it is thereby that it becomes feasible to switch over from the one to the other switching position without the necessity to A interrupt the high frequency energy supplied to the waveguide switch.

As a result of the fact that the vane 18 in each of its two switching positions is symmetrically situated with respect to the two waveguides that are interconnected by the said switch, the passage through said switch for the high frequency electro-magnetic energy seems practically straight so that a minimum power loss between the connected waveguides is attained.

In the embodiment of the vane 18 as shown in FIG. 4 the said means 22 and 23 each consists of a single traverse plate. The vane, however, can also be of the shape shown in FIG. 5, in which the rotatable vane at its short edges is provided with a number of narrow rectangular traverse plates 45 and 46 respectively which are arranged equidistantly in a plane which is perpendicular to the direction of the shaft, each of the said rectangular traverse plates being divided into two equal parts by the plane of the vane.

It may further be observed that the waveguide switch according to the invention is in no way restricted to the use of the eletro-magnetic driving means described. Several other known driving arrangements may be used. It is also possible to use a single driving arrangement instead of two equal and separate driving means, whereby in that case, the vane is held in the one position by means of a spring and is brought in the other switching position by means of the said single driving arrangement which moves the vane against the force exerted by the said spring.

Finally it may be observed, that with a practical em bodiment of the waveguide switch according to the invention, using a vane as shown in FIG. 4, the following dimensions gave satisfactory results over a wide frequency band:

Height of the gap 0.0151 Length of the rectangular traverse plate 0.023A Width of the rectangular traverse plate 018A What I claim is:

1. A waveguide switch of the type comprising, a deltashaped body having first, second and third waveguide passages passing normally inwardly from the flat faces of said body respectively to intersect in the central portion of said body at angles of with respect to each other; a vane of rectangular dimensions; a shaft secured to one longitudinal edge of said vane and means in said body rotatably mounting said shaft in alignment with the line of intersection of the two adjacent walls of said second and third passages, the improvement wherein the said rotatable vane is provided with means fixedly connected to the short edges of said vane normal to said shaft and forming a capacitive coupling with the adjacent internal Walls of the said switch body parallel to said last mentioned edges, whereby said capacitive coupling functions as a short circuit for high frequency energy supplied to said switch.

2. A waveguide switch as claimed in claim 1, wherein the short edges of said vane are longer than the width of said waveguide passages and the longitudinal edge of said vane is smaller than the height of said waveguide passages.

3. A waveguide switch as claimed in claim 1, wherein the said means which are fixedly connected to the short edges of said vane consist of rectangular traverse plates positioned on said short edges in planes normal to the plane of said vane, each of said plates being divided into two equal parts by the plane of the vane.

4. A waveguide switch as claimed in claim 1, wherein the said means which are fixedly connected to the short edges of the said vane each consist of a number of narrow rectangular traverse plates equidistantly arranged in a plane perpendicular to the direction of the shaft, each of the said rectangular traverse plates being divided into two equal parts by the plane of the said vane.

5. A waveguide switch as claimed in claim 1, wherein the said waveguide switch is provided with at least one driving arrangement for rotating the said vane from the one to the other switching position, said driving arrangement comprising a coil and a plunger which is rotatably mounted in said coil and which is coupled to the said shaft.

6. A waveguide switch comprising a body member having first, second and third waveguide passages extending inwardly from flat external faces and intersecting each other at a junction in the central portion of said body at relative angles of 120", a rectangular vane pivotally mounted in said central portion on an axis that extends along an internal wall of said central portion at the junction of said first and second passages, said vane having a dimension normal to said axis sufiicient that it extends into said third passage, the dimension of said vane parallel to said axis being less than the corresponding dimension of said central portion, and transverse plate means mounted on each edge of said vane that is normal to said axis with the plane of said vane substantially bisecting each of said plate means, whereby said plate means and the internal walls of said body parallel and adjacent thereto form capacitive couplings that are substantially short circuits for high frequency energy applied to said passages.

References Cited UNITED STATES PATENTS 3,009,117 11/1961 Lanctot 3337 HERMAN KARL SAALBACH, Primary Examiner.

M. NUSSBAUM, Assistant Examiner. 

